The present invention relates generally to knee bolsters for vehicles and, more particularly, to an energy absorbing knee bolster assembly for a vehicle.
It is known to provide a vehicle interior with a knee bolster assembly that straddles a steering column at a location below a steering wheel and generally on a lower portion of an instrument panel for a vehicle such as an automotive vehicle. Typically, the knee bolster is designed to absorb the impact of an occupant""s knees during a forward collision as a means of supplementing seat belts and other occupant restraints.
An example of such a knee bolster assembly is disclosed in U.S. Pat. No. 6,145,880 to White et al. In this patent, the knee bolster assembly includes a central bracket adapted for partially surrounding the steering column and a foam element mounted on the central bracket. The knee bolster assembly also includes left and right knee brackets mounted on opposite sides of the central bracket. The knee brackets each have a generally D-shaped cross-section including a convex rear wall positionable adjacent a vehicle driver occupant such that upon loading by the vehicle driver occupant, the knee brackets deform about multiple, nonspecific bend lines for absorption of energy. The knee brackets preferably include inner and forward walls rigidly secured to the central bracket and outer and rear walls that significantly deform for absorption of energy. The central bracket and knee brackets are separate parts formed as three progression steel stampings.
Although the above knee bolster assembly has worked, it is desirable to provide a new knee bolster assembly for a vehicle. It is also desirable to provide a knee bolster assembly having a thermoplastic knee deflector and energy absorbing knee bolster brackets. It is further desirable to provide a knee bolster assembly that has a thermoplastic knee deflector and energy absorbing brackets that use a one-piece design. Therefore, there is a need in the art to provide an energy absorbing knee bolster assembly for a vehicle that meets these desires.
It is, therefore, one object of the present invention to provide a new energy absorbing knee bolster assembly for a vehicle.
It is another object of the present invention to provide an energy absorbing knee bolster assembly for a vehicle that has a thermoplastic knee deflector and energy absorbing knee bolster brackets.
It is yet another object of the present invention to provide an energy absorbing knee bolster assembly that has a one-piece design.
To achieve the foregoing objects, the present invention is an energy absorbing knee bolster assembly for a vehicle. The energy absorbing knee bolster assembly includes a knee deflector for partially surrounding a steering column of the vehicle. The energy absorbing knee bolster assembly also includes left and right energy absorbing knee bolster brackets on opposite sides of the knee deflector. The knee deflector and energy absorbing knee bolster brackets are integral, unitary, and one-piece.
The energy absorbing knee bolster assembly has a one-piece design that replaces three steel stampings in the current manufacturing process. The energy absorbing knee bolster assembly also allows for tuning the stiffness of the knee deflector by including gas assisted tubes to stiffen the knee deflector. The energy absorbing characteristics of the knee deflector may be tuned by altering or varying the wall thickness of these tubes by the amount and pressure of the gas injected during the molding process without requiring a tooling change. The energy absorbing knee bolster assembly may have several different stiffness parts that can be produced in the same tool to allow the parts to be evaluated to obtain the best femur loads for a given vehicle pulse. Further, the energy absorbing knee bolster assembly eliminates three progression steel stampings with one injection molding tool and provides a tunable part for energy absorption, without tooling changes. The energy absorbing knee bolster assembly requires only the process of gas assisting and foam durometer to adjust the stiffness of the assembly. The knee bolster brackets are filled with frangible foam to increase the crush force required and to allow the brackets to be tuned to the vehicle crash pulse by varying the durometer of the foam, allowing the stiffness to be altered without changing the tool.
Other objects and features of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings.